Re: [PATCH] tpm: remove type and name fields from the I2C Infineon OF table entries

On Mon, Dec 04, 2017 at 06:39:16PM +0100, Javier Martinez Canillas wrote:> The commit 21dc02eab989 ("tpm/tpm_i2c_infineon.c: Add OF attributes type> and name to the of_device_id table entries") added type and name fields> to the OF device ID table entries for the I2C Infineon TPM driver.> > The only justification for the change in the commit message is that it's> probably a good idea to have these fields populated in the OF entries.> > But I don't think that's true. In fact, I believe that's not correct to> add these fields for the following reasons:> > * The struct of_device_id .type field matches the device_type property> in the Device Tree nodes. The ePAPR document says that new use of the> property is deprecated and should only be included in cpu and memory> nodes for compatibility with the IEEE 1275-derived Device Trees.> Also, mainline Device Tree source files don't include this property> in the TPM nodes defined.> > * The struct of_device_id .name field matches the Device Tree node name> but the ePAPR document says that the node name should be generic and> reflect the function of the device, not it's programming model. So in> the case of TPM chips, it should just be "tpm" but the name fields are> set in the OF table entries to the actual device model (i.e: slb9645tt).> > Now, from a practical point of view this means that the OF module aliases> for the supported devices include the name and type of the device entries:> > $ modinfo drivers/char/tpm/tpm_i2c_infineon.ko | grep alias> alias: of:Nslb9645ttTtpm*Cinfineon,slb9645ttC*> alias: of:Nslb9645ttTtpm*Cinfineon,slb9645tt> alias: of:Nslb9635ttTtpm*Cinfineon,slb9635ttC*> alias: of:Nslb9635ttTtpm*Cinfineon,slb9635tt> alias: of:Ntpm_i2c_infineonTtpm*Cinfineon,tpm_i2c_infineonC*> alias: of:Ntpm_i2c_infineonTtpm*Cinfineon,tpm_i2c_infineon> > But since the device_type isn't set in the tpm DT nodes and the node name> is a generic one, the reported MODALIAS when a device is registered via OF> won't match the driver's module aliases:> > $ cat /sys/class/tpm/tpm0/device/modalias> of:NtpmT<NULL>Cinfineon,slb9645tt> > So remove these fields from the OF entries to allow the module aliases to> match the MODALIAS reported by the kernel when the device is registered:> > $ modinfo drivers/char/tpm/tpm_i2c_infineon.ko | grep alias> alias: of:N*T*Cinfineon,slb9645ttC*> alias: of:N*T*Cinfineon,slb9645tt> alias: of:N*T*Cinfineon,slb9635ttC*> alias: of:N*T*Cinfineon,slb9635tt> alias: of:N*T*Cinfineon,tpm_i2c_infineonC*> alias: of:N*T*Cinfineon,tpm_i2c_infineon> > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>